What was lost
by Eledhwen
Summary: A crossover with the Sarah Jane Adventures, and set after S3 and Voyage of the Damned as well as after S1 of SJA. A meeting of old friends.


_**Disclaimer:**__ How I wish I owned them! Anyway, I don't; they're the property of the BBC._

**What was lost**

The aliens had gone squish - literally, this time - the world was saved. Again. They filed out of the factory, brushing bits of alien off their clothes.

"Fancy a hot chocolate?" asked Sarah Jane, fishing in her handbag for car keys. "I got some marshmallows."

"Right now, a shower's all _I'm_ after," said Clyde, with disgust. "Why can't they ever disintegrate cleanly?"

Sarah Jane opened her mouth to reply, but the words were whisked away in the sudden breeze that had blown up. And with the wind, a noise.

The children were staring at a spot not twenty metres away, where swirling bits of rubbish were being replaced by a tall, solid, and very familiar blue box.

"What the …?" exclaimed Clyde.

"What's a police box?" Luke asked.

"Where did it come from?" Maria added.

Sarah Jane gripped her handbag, and wondered who would come out of the TARDIS's door. A Doctor she recognised, or one she didn't?

Pinstripes emerged, attached to a skinny body and an anxious face, and an arm wielding a sonic screwdriver. She relaxed - a Doctor she knew, then, and a Doctor she had rather liked.

He looked around, glancing past Sarah Jane and the astonished teenagers before jerking his gaze back to her.

"Sarah _Jane_!"

"Hello," she said.

"Got a distress signal," he said.

"Already taken care of," Sarah Jane returned. "Beat you to it, Doctor."

Behind her, she heard Maria breathe "the Doctor?"

"Oh," said the Doctor. "Good. You okay?"

"Absolutely," said Sarah Jane. "Nothing a shower won't take care of."

"Good. That's good. Well done," said the Doctor, scratching his head. "I'll be off, then." He turned, and opened the TARDIS door, before pausing and looking over his shoulder. "Hang on, how did you find out about this before me?"

"I learned from the best," said Sarah Jane. "And I'm here, on the ground. And my computer's patched into UNIT."

"UNIT!" He beamed. "Still going, are they?"

"Still going."

"And you?" he asked, turning properly away from the door.

Sarah Jane held out her hand. "I'm good, Doctor. And there are people I want you to meet. People who I think would like to meet you. You can't try and tell me you don't have time."

He visibly hesitated, before giving in with a shrug. "Oh, all right then."

He followed her across to the children, who were hopping with excitement.

"My neighbour, Maria Jackson," said Sarah Jane. "Clyde Langer. And my son, Luke." The Doctor gave her a quick, penetrating glance. "Adopted," Sarah Jane added, although she hadn't planned to. "This is the Doctor. My Doctor."

"Hello," said Maria.

"Cool!" Clyde said.

"How do you do?" Luke concluded, politely.

The Doctor stuck his hands in his pockets and regarded them all, one by one, lingering on Luke. His eyes narrowed. "Your timeline's all wrong," he said.

"We know," Sarah Jane said, quickly. "It's a long story. The children and I were just going home for hot chocolate …"

"… and showers," Clyde put in.

"And showers. Will you come, Doctor?" She smiled at him, encouragingly, hopefully. "Marshmallows."

"Oh …" The Doctor fidgeted. "Oh, all right, then." He looked back at the TARDIS. "I'll just leave her here."

Sarah Jane found herself beaming. "Luke and I will go ahead in the car, put the kettle on. Maria, Clyde, will you show the Doctor the way?"

"Sure," said Maria. "C'mon."

Sarah Jane ushered Luke into the car and set off, waving at Maria, Clyde and the Doctor in his long coat walking next to them.

"Your cheeks are red," Luke observed, as they took the corner slightly too fast.

"Are they?" Sarah Jane glanced quickly at him. "It's a warm day. All that running."

Luke grinned. "It's because of him, isn't it?"

"Don't be ridiculous," she said.

He fell silent - trust Luke, to be sensitive to her feelings - until they had pulled up outside the house.

* * *

Maria and Clyde waited while the Doctor disappeared inside the TARDIS, muttering something about making sure the ship was all right.

"It's tiny, that thing," said Clyde.

"Sarah Jane says it's bigger on the inside," Maria returned.

"Bigger on the inside? That's impossible."

"Very few things are impossible," said the Doctor, emerging from the blue box and closing the door firmly. "My TARDIS isn't one of them. She's entirely possible, including the bigger on the inside part."

"Can we see?" asked Maria, reaching out but not quite daring to touch the side of the ship.

"Maybe later," the Doctor said, giving her an appraising look. "Not now, don't want to incur Sarah Jane's anger if we have cold hot chocolate."

The children fell into step beside him. "How did you know something was wrong here?" Maria questioned.

"Distress signal," said the Doctor, glancing down at her. "The TARDIS is programmed to pick up distress signals, especially if it's from Earth. So I came running. Too late. Do you save the world often?"

Clyde and Maria nodded. "Seems like every weekend," Clyde said. "We've had abducting aliens, and a Gorgon …"

"The Bane, they were first. Slitheen, twice," Maria added.

"The Slitheen? Again?" The Doctor grimaced. "What were they after this time?"

"Money," said Maria, wondering when he had met the Slitheen.

"But you dealt with them?"

"Vinegar!" said Clyde. "Sploosh."

The Doctor seemed impressed. "Well done. Who worked that one out?"

"Me," said Clyde.

"Knew a boy like you once," said the Doctor, a little absently. "Well, man, really. A good man. Everyone thought he was the idiot - but he helped save the world too. Several times."

"What happened to him?" asked Maria.

"Mickey the Idiot?" The Doctor's eyes, when she looked at them, were distant. "He's living in a parallel world."

"But they're impossible!" exclaimed Clyde.

The Doctor raised his eyebrows. "What did I just say about impossible? They're all around us, but we can't get to them."

There was something final in his tone, and Maria shook her head at Clyde as he opened his mouth to ask another question.

"So tell us about Sarah Jane," Maria said. "How did you meet her? What was she like?"

He brightened considerably at the question, and launched into a story about kidnapped scientists and strange aliens. It lasted for the rest of the walk to Bannerman Road, giving Maria plenty of time to study the Doctor properly. It was odd, she thought; although she knew he was technically an alien - and possessed a time-travelling, space-squishing ship - he could have been just any bloke. No; she revised that thought. Not any bloke. There was something about the way he talked, the way he looked at you, that made you want to listen to him, she thought. Made you want to do whatever it was he suggested. And he was clever, that was clear. Maybe cleverer than clever. Maybe the Doctor could help Luke, help him understand life better.

The Doctor ended his story as they turned into Bannerman Road. "So I agreed Sarah Jane could travel with me. And she did, for some time."

"Why did she stop?" Maria asked.

He paused. "I was called home. She couldn't come. I … left her."

"Where?" said Clyde, his tone hushed.

The Doctor began walking again. "Aberdeen. Bit of a geographical mistake. So, is this it?"

* * *

Luke watched Sarah Jane bustle about the kitchen. "When did you last see him?" he asked, as she got out mugs and prepared a plate of biscuits.

"Oh." She opened the fridge for milk and poured it into a saucepan. "About eighteen months ago?" Sarah Jane paused, holding the milk carton. "I hadn't seen him for so long, and he was so different, but he hadn't really changed at all. And I suppose I realised I'd wasted too many years waiting for him." She put the lid on the milk. "Sorry, there I go, getting all emotional. Take the biscuits through to the lounge, will you?"

Luke slid off the kitchen counter and did as she asked.

The Doctor, Maria and Clyde arrived about fifteen minutes later, by which time Sarah Jane had moved cushions five times and rearranged photographs twice. Luke noticed Maria's eyes were shining in the way they did when she was excited about something, and even Clyde was looking at the Doctor with approval.

Sarah Jane poured hot chocolate, and they all sat down in the lounge with steaming mugs. Luke watched the Doctor pick off his marshmallows first, eating them absently while looking round the room with keen eyes, taking everything in.

"So," said the Doctor, putting his mug down, "you're with UNIT?"

"Just cooperating with them, when needed," Sarah Jane said. "I couldn't work with them. Too much bureaucracy. I like my independence."

"You learned from the best," he said, and they exchanged smiles. "Sarah Jane Smith," the Doctor went on, "saving the world."

Sarah Jane cradled her mug, and Luke sensed she was steeling herself to ask a question. "Doctor - where's Rose? Are you alone? What happened at Canary Wharf?"

Luke could feel the Doctor's barriers snap up, an almost-perceptible change in the atmosphere of the room. "She's fine. She's safe. I'm just … travelling. There was an amazing starstorm in the Casseiopeia Belt the other week. The planet Sto just voted through rights for cyborgs, imagine that; wouldn't've been possible just a decade ago. But more importantly, what's been going on here? Slitheen?"

"Nothing much recently," said Sarah Jane. "Just the odd minor invasion, now and then. You know how it is. Even Christmas was quiet this year."

The Doctor dug around inside his suit. "Good. Glad to hear it. Now …" he pulled out a neat little silvery gadget. "Let's have a look at you, Luke."

Everyone turned to look at Luke. He had been half-expecting the Doctor to say something like this, ever since that penetrating first examination. Standing up, he nodded. "Okay. What do you want to do?"

"Find out where you come from," said the Doctor, raising an eyebrow. "Won't hurt." He flicked the gadget, which emitted a blue light and a whir. "Bit of scanning with the old sonic, that's about it."

"What will it tell you?" asked Maria, appearing nervous.

"Don't know until I do it," the Doctor said, cheerily. "Luke?"

He nodded again. "I'm ready."

The Doctor pressed a button on his sonic screwdriver, and ran it slowly up and down Luke's body. It tingled, a little, but otherwise he felt nothing.

"Hmm."

Sarah Jane, who had been sitting on the edge of her seat watching intently, started. "What does that mean?"

The Doctor put the sonic screwdriver away and looked at her. "Generally, I think it means 'ah, interesting', although it has been known to mean 'yes', and just occasionally, 'I'm sorry, I wasn't really paying attention'." He grinned, cheerfully.

She folded her arms. "What does it mean now?" Her voice, Luke noted, had that slightly steely edge she usually used when she wanted him to do something.

"Oh." The Doctor sat down again, leaning one bony elbow on an equally bony knee. Evidently the voice worked on aliens as well as human boys. "It means Luke is, biologically at least, entirely human. Whoever put him together did an excellent job. Can't see the joins. Biological age of a 13-year-old - all the fun bits to come - healthy, good solid internal organs, _excellent_ circulation, and you'll put on a bit of a growth spurt in a year or so," he added, in Luke's direction. "Try basketball. Or rowing."

Sarah Jane relaxed. "Good. Great!"

Crossing to her, Luke patted her shoulder. "See, Mum, I told you."

She took his hand.

"Of course," the Doctor went on, rubbing the back of his neck apologetically, "that's biologically. Psychologically, might be different." He glanced at Luke, rather, Luke thought, as if he were an interesting laboratory specimen. "I could take a look," he added, hopefully.

"Inside my head?" asked Luke, sensing a light pressure at the edge of his mind.

"No," Sarah Jane cut in. "He's had enough people messing with his brain. He's not an experiment, Doctor, he's a boy."

"Weeeell," said the Doctor, "he _was_ an experiment. I wouldn't hurt him. You know that."

"Maybe not intentionally," said Sarah Jane, putting her arms around Luke. "I'm worried about accidentally." She rose. "If it will help, without you invading his head, I'll show you all the data we have."

* * *

Really, it was remarkable, the Doctor thought, as he followed Sarah Jane - Sarah Jane Smith! - and her gaggle of children up the stairs of her house and into an attic, how little humans changed. She was still the same obstinate, independent, remarkable girl he'd met all those years, all those regenerations ago.

Now, she led the way into a cluttered room full of pictures and gadgets, quite a number of which he recognised.

"You kept all this!" he said, turning to her with delight.

Sarah Jane smiled at him. "I'd be a fool to throw it away."

He returned the smile, and pounced on an object. "A musical box from the Borgon Archipelago! Where did you get that?"

"In an antiques shop, ten years ago," Sarah Jane said, as he fiddled with the controls and got the box playing its weird, sweet music. "I never managed to make it work."

"Oh, I'm good with stuff like this, me," the Doctor said, glancing up and seeing pure human wonder on the faces of the three children. His former companion was watching him indulgently.

"Do you want to see that data?" she asked.

He put the box down, where it whirred to silence, and stuck his hands in his pockets. "Show me," he said, looking at the wonderfully boxy computer.

Sarah Jane raised an eyebrow at him, turned to the brick wall, and said, "Mr Smith, I need you."

There was a clunking of mechanics and to the Doctor's astonishment, the wall opened and out emerged a large and evidently powerful computer. "Yes, Sarah Jane?" it said, in a well-modulated voice.

She looked at him with a smile on the corner of her lips.

"That's not a human computer," he said, after a moment, giving her his best severe look and trying not to show her his surprise.

Sarah Jane folded her arms. "No, it's a Xylok. He's been very useful. Mr Smith, please supply the Doctor with all the data we have on Luke."

The computer buzzed. "Certainly, Sarah Jane." After a few moments, it produced a slip of blueprint, which Sarah Jane handed to the Doctor with a flourish. He scanned it quickly without bothering to put on his glasses - Sarah Jane knew, after all, he didn't need them.

"Just tells me what I told you downstairs. Apart from the fact Lukey-boy here was most certainly _not_ born 13 years ago, he is, to all intents and purposes and appearances, a perfectly normal 13-year-old boy. I told you, your …" he waved a hand at the computer, "Mr Smith told you, and I daresay Luke could've told you. It's his head I'm interested in."

Sarah Jane, her eyes flashing, shook her head. "And I told you you're not getting in there."

"What about me?" Luke put in. The Doctor spun to face him. There was definitely something there, a latent, untrained telepathic energy, creeping out tentative tentacles to investigate. He sent soothing, encouraging thoughts back.

"It wouldn't hurt," he said. "You can close off anything you don't want me to see."

Luke turned to Sarah Jane. "I trust him," he said.

The Doctor found himself grinning his reassurance grin at Sarah Jane. "See? He trusts me. Quick learner." _Too quick_, said a little voice.

He pushed the thought away, and flexed his fingers, clearing his mind. "Right," he said, firmly. "If there's anything you'd rather I didn't see …"

"Bring up a door," said Luke, nodding.

"Good," said the Doctor, wondering just what he would find in this strange boy's head. "All right, then."

He raised his hands. Funny how this regeneration found the physical touch a help. Maybe it was age - there was a time when this would not have been necessary. But then so many things had changed.

The last time he'd tried this had been with the mad architect, Peter Street. A mind like a maelstrom, once brilliant and sharp, now twisted and confused. Before that, Reinette, Madame de Pompadour - clear, cool, refreshing, and oh so keen.

Luke's mind, by contrast, was young. So young, and still growing, rather like the green shoot from the branch of a tree. But even as the Doctor looked, the shoot grew and put forth a small leaf. And there was another branch, and another, and another. Luke's mind was a work in progress, but developing faster than anything the Doctor had seen before.

"Stars!" breathed Luke, softly.

"Hey!" The Doctor closed the chink Luke had seen through. "I'm supposed to be examining you."

"Sorry," said Luke.

The Doctor refocused on Luke, picking through the branches. There was a patch of warmth and light, shining through the new leaves of Luke's mind. Love - love, for Sarah Jane, he realised, touching it gently with his own thoughts. Luke responded with an enthusiastic _yes!_, and the Doctor smiled.

Close to the warmth there was a tangle of uncertainty - young uncertainty, the Doctor decided. Here were Luke's worries about fitting in at school, about understanding the world, about girls. He went past them, expecting a door at any moment; came out through the branches - and halted his exploring. Here was nothing; here was an empty space, waiting to be filled by thoughts and emotions and feelings and knowledge.

"Doctor?" said Luke, quietly, nervously.

"S'all right," the Doctor murmured, reaching cautiously into the void. It did not feel malicious, or dangerous. Just empty.

He relaxed, and withdrew his mind from Luke's, letting his hands drop.

* * *

The Doctor took his hands from Luke's head, and stepped away. Clyde wondered if that was good news, or bad. He could not read anything into the Doctor's expression as he looked at Sarah Jane.

"Well?" said Sarah Jane.

Next to Clyde, Maria was fidgeting nervously.

"So is he going to be, like, the next Einstein?" Clyde asked, and found a pair of raised eyebrows directed at him.

"Einstein? Pffft!" said the Doctor. "He's got nothing on Luke here. You might have the body of a 13-year-old, Luke, but you haven't got the mind of one."

Sarah Jane came quickly to Luke and put her arm around his shoulder. "Is that bad?" she asked.

The Doctor shrugged, and sat down. "Not bad. Risky, but not yet bad." He turned to Luke. "Your head, Luke, is why your timeline feels wrong. It's like a blank computer disc, waiting to be filled with stuff. There's a bit on there, but you've got gigabytes of memory to be used. Whoever built you didn't load anything in there, nothing of any value in any case, so you're filling it up with everything you see, everything you hear." He ran a hand through his hair. "I've never seen anything like it."

There was silence. Sarah Jane looked upset by the Doctor's diagnosis. Clyde folded his arms.

"But he's not like a broken computer, right?"

"Oh, there's nothing to fix," said the Doctor, cheerfully. "Luke is most definitely not broken. Quite the opposite, actually."

Maria let out a squeak, and hurried over to hug Luke and Sarah Jane.

"So when I mentioned Einstein …" Clyde pursued.

"Clever bloke," agreed the Doctor, "though it's not like he came up with all his findings himself."

"You," said Sarah Jane, "are an incorrigible show-off."

The Doctor beamed at her. "Absolutely. Every time. Your Luke needs a proper education, Sarah. Quite apart from the Slitheen risk - though hopefully they won't be back again, and if I never have to go back to Raxacoricofallapatorius I'll be happy - whatever local comprehensive you're sending him to won't do. They won't understand him in a year. He needs better minds than that."

Clyde looked at Maria, wondering if he'd understood the Doctor correctly.

"He's too young," said Sarah Jane, flatly. "He's barely lived. He's not going with you."

"I can give him what he needs," the Doctor returned. "The greatest teachers, across the galaxies. Newton. Galileo. Agra … well, minds you wouldn't have heard of."

"To do what, Doctor?" Sarah Jane asked. "He's human. Can't you let him be just human?"

"He'll never _be_ just human, Sarah," the Doctor said.

Clyde thought that was unfair, and said so.

"What's wrong with being human?" he asked. "Can't be that bad, look at you."

The Doctor straightened up, and looked very directly at Clyde. "Your basic bipedal shape is common across the universe," he said, something in his tone that made Clyde feel very small. "It's what's inside that makes the difference."

"Doctor …" put in Sarah Jane.

"Nah, it's all right," Clyde said. "See here, Doctor, or whatever you're called. Luke's our mate. He's a bit daft sometimes, and he hasn't got a clue about girls or footie or anything that really matters, but we'll stick by him. And he might be the next Einstein, but he still needs to pass some exams."

There was a tense silence. Next to him, Maria bit her lip. Sarah Jane was smiling in a peculiar, tight way, her arm around Luke.

The Doctor, expressionless, turned to Luke. "What do you want?"

"To be normal, but that's not going to happen, is it?" Luke asked.

"No."

Luke looked at Maria and Clyde. Clyde gave him a grin. "You can be brainy and normal. Ish."

"Please stay," said Maria.

"If … if I want to come later, can I?" asked Luke. "Clyde's right. Exams would be useful, if I want a job. I'd quite like a job."

"I can't force you to come now," admitted the Doctor. "But I can't promise to come back for you."

"I'll take the chance," said Luke. "I'm staying."

For a moment, Clyde thought about trying to be masculine about the news, but gave up in a whirl of hugs and laughter.

* * *

Sarah Jane sent the children away to clean themselves up after the day's events, and sank down in a chair to watch the Doctor. He was fiddling with Mr Smith; she found she could not be bothered to remonstrate or ask him to stop. In any case the very nature of the fiddling was reassuring - he had not changed so very much after all.

"Will you come back for him?" she asked, as he frowned over the computer.

"Eh?" The Doctor straightened up.

"Luke," Sarah Jane pursued. "Do you think you'll come back for him?"

He paused, the blue light of the sonic screwdriver flickering over Mr Smith and lending his face a suitably alien glow. "How can I say?" he replied. "Anything could happen - you know what I'm like, I could … anything could happen."

"You're avoiding the question," said Sarah Jane.

The Doctor turned the screwdriver off, and sat down, somewhat heavily, to face her. "No. Probably not. I haven't … I'm not very good at looking after people, these days. I've lost so many people."

"Rose?" asked Sarah Jane, daring to ask the question he had avoided earlier.

He steepled his hands and rested his chin on them. "She's safe, you know, but she's trapped, in a parallel universe. Can't get out. I can't get in. But she's just one person, one of so many I lost." The Doctor paused. "Do you remember Harold Saxon?" He said the name in a strange, halting way.

Sarah Jane thought back to the odd day when the President of the United States was assassinated on live television. "Were you on the _Valiant_?" she asked.

He nodded. "Saxon - I suppose you wouldn't have seen it, there was no reason …"

"I voted for him," Sarah Jane said. "I think most people did. A pity he was killed. What happened?"

"He was the Master," said the Doctor. "I wasn't alone. I wasn't the last." He kept on talking, the story spilling out with names of people Sarah Jane had never met but hoped she would at some point. And the story continued, into events she did remember - Christmas, just a few months before, and the spaceship that did not hit Earth, and a girl called Astrid who was just stardust. He seemed to want to talk in a way her old Doctor had never done, so she listened, prompting him with questions now and again.

"So I ran, for a bit," he said. "Went star-gazing at the edges of the galaxy. Tried surfing the rings of Saturn - I used to enjoy that. I wanted to avoid this place."

"But you _like_ Earth," said Sarah Jane. "You've always said how much you like Earth."

He smiled, but it was a hollow smile. "Oh, yes, I love it. Love all of you. You're brilliant. But that's the problem - what you love, you can hurt. Not sure I want to hurt you all, any more. Don't think I can lose any more of you."

Sarah Jane reached out, impulsively, and took his hand. "The Master wasn't your fault."

"Wasn't he?" The Doctor looked at her. "You sure?"

She decided she would not pursue that line of questioning. "Anyway, you didn't lose me. I'm fine. Better than fine."

The Doctor suddenly grinned, properly. "Yes, you are! My Sarah Jane."

Neither of them said anything for a few moments. Sarah Jane studied his face, at the angular ageless features that were so strange and yet eerily familiar. "I don't think," she said, slowly, "that any of them would have regretted meeting you, Doctor. Not even Astrid. And if you want to come back, for Luke, I won't stop him going with you, if he wants to."

He stood, and came to give her a bone-crushing hug. "Will you do something for me?"

"Of course."

He pulled an envelope from his pocket. "Pass this on to UNIT for me. It's about Martha Jones. And …" he dug around for a moment, before Sarah Jane wordlessly handed him a pen and a piece of paper. "Oh. Thanks." He scribbled, and gave her the paper. "Look Martha up, sometime; I think she'd like to know you. And if you're ever in Cardiff …"

Pinning the addresses to the wall, Sarah Jane nodded. "I'll go. What will you do now?"

"Dunno." He stuck his hands in his pockets. "See where the TARDIS wants to take me."

"Find someone?" Sarah Jane said. "If you don't want to come back immediately, for Luke when he's a bit older; find someone else."

The Doctor looked hard at her. "Someone else said that to me. Not that long ago."

"They gave you good advice, then," she said, touching his shoulder. He responded with a smile that told her he would not seek out a new companion - not yet, anyway. She wished she could understand, but as they left the attic and the Doctor followed her down the stairs, chattering away again about her alien trinkets, she knew she never would completely understand him.

He picked up his coat and refused her offer of a lift back to the TARDIS.

"I'll find my way. The walk'll do me good."

"The children will be furious when they find you've left without them seeing the TARDIS," Sarah Jane pointed out.

"Tell them … oh, you'll work something out," the Doctor said. "You're better at that than me."

Sarah Jane nodded. "I'll find something to tell them."

"This is why I keep coming back," he said, half-turned away. "This is why the Earth's worth saving. Makes me glad I didn't lose you too. Goodbye, Sarah."

She raised a hand, and, leaning on the doorframe, watched him walk away, coat flapping. And this time, there was no empty feeling inside. Somehow, Sarah Jane knew he'd be back - maybe with a different face, maybe in thirty years when she was old and grey and he'd been gone two minutes - but he was her Doctor. Whatever else happened, that, at least, was a constant.


End file.
